of rochester



30 such a trade or designating Patented Nov. 1923.

UNITED STATES 1,415,413 PATENT OFFICE.

THEODORE B. DRESCHER, OF ROCHESTER, NEW YORK, ASSIGNOR TO BAUSOH & LOMB OPTICAL COMPANY, OF ROCHESTER, NEW YORK, A CORPORATION OF NEW YORK.

LENS AND BLANK THEREFOR K Drawing.

To all whom it may concern:

Be it known that I, THEODORE B. DRE- somm, of Rochester in the county of Monroe and State of New York, have invented certain new, and useful Improvements in Lenses and Blanks 'lherefor and Methods of Marking Them for the Purpose of Identification; and I do hereby declare the following to be a full, clear, and exact description of the same.

My resent invention relates to lenses and lens'b anks, and particularly ophthalmic lenses and the blanks from which they are made, and has for its object to provide such 1 articles with marks or characters which will enable them to be identified at all times whether com leted or in such form as to require a furt er manipulation or treatment to adapt them for the particular purpose intended.

Heretofore considerable diflicult has been experienced by manufacturers o lenses and lens blanks in placing designating, identifying or trade marks upon them in i such manner that, whether the lenses are completed or the lens blanks are finished with one surface ground and polished, the

product of a particular manufacturer can be recognized and distinguished. Unless mark is ineradicabl marked in the artlcle itself, there is a liability that unscrupulous dealers may pass ofi on the public or substitute the roduct of one manufacturer when those 0 an 86 other are called for or desired, but by the invegtiitan hereinaftelil' dgscribed this is ]prevent cau t eesignat' mar or desi td be fi i' ied in the 18 g of which the ens or blank is compose in such man- 40 ner that while it does not interfere with the purpose for which the article is intended, namely, the free passage and refraction of light rays, it nevertheless serves as an identifying means under all circumstances. 6 In carryin out m invention I utilize in a commercia way t e fact well known to those skilled in the art, that the light transmitting properties of glam and particularly of optical g ass used in the manufacture of lenses, can be altered or modified slightly by subjecting it to the action of t e rays emanating from a vacuum tube through which a current of electricity is passed embodying an anode or terminal of metallic AND METHOD or MARKING IT 4 IDENTIFICATION.

Application filed November 25, 1921.

' in the non. 'rnn runrosn or Serial No. 517,476.

affected visible by imparting to them a slight and usually a violet color, which however, when not very deep in tone does not appreciably detract from the refracting powers of the lens or its light transmitting properties. The composition of the glass is afl'ected all the way through from the incident to the emergent surface so that the markmgs cannot be removed by subsequent grindin or polishing operation. I have found t at an ophthalmic lens for correcting defects in vision, such as spectacle lens, is qulte as eflicient when a limited portion or ortions of the less of which it is composed ave been sub ected to the action of the infra-red or ultra violet rays whichever may produce the effect, emanatin from such a tube to alter or modify a portion of the composition slightly or suificient to render the mark visible under some circumstances. I

am unable to state whether this characteristic of non interference with the normal use of the lens is due to the peculiar tint of the altered or modified portion but I have, by (practical use, found it to be as stated! phthalmic blanks and lenses are placed upon the market by the manufacturer in three ways (1) in the form of plain blanks of fine optical glass, (2) with one surface only ground an polished so that the optician may finish the other surface and (3) orm of lenses with both surfaces finished, that is ground and polished. Such 'blanksor lenses may have embodied in their substance, the trade mark or desi ating mark as a design or initials indicatlng the manufacturer, by placing over one of their surfaces a mask or stencil formed of a material such as lead that is impermeable to the rays which aflect the composition of the glass whether ultra-violet or infra-red,

said stencil having portions .cut .away or I removed to form an openin correspondin to the design or mark to is applied an permitting the emanations from a vacuum tube, such as described, to fall upon'the len through the open spaces and excluding them from the arts coveredby the mask.

By this means t e material of the lens will be modified or altered clear through from one surface to the other. The length of time to which the glass is subjected to these rays, is comparatlvely sli ht, say only a I few seconds, so that whi e a very faint violet or purple image is formed which is visible u on certain methods of inspection only, suc 'as placing itupon a white surface this discoloration is imperceptible to the person usin the lenses in the ordinary way. It isobvlous that with the designat "ing/or trademark thusindicated or marked in the glass itself and clear through its substances it cannot be removed by alteration of the surfaces as in rinding and polishing the lens or lens 'b anks to suit the peculiarities of the patient, and yet the lenses or blanks made by a manufacturer can be readily distinguished.

While the invention is particularly adapted for use in connection with ophthalmic lenses and lens blanks as these are not provided with tubes, shells or holders, which could bereadily marked with a trade mark, it can nevertheless be utilized to inevitably mark or designate'other kinds of lenses, as

for instance telescopic or photographic objectives or eye pieces in which the mark may be placed 1n some position where it would not materially or unduly affect the light transmitting properties of the lens nor its refracting power.

particular I claim as my invention: 1. A transparent refracting lens of lass having a portion of the material of w ich' it is composed slightly modified or altered in the form of a desi ating mark less in area than the surfaces t ereof, said'marking or tinting extending through the lens from one surface to the other. i

2. A transparent refracting lens of glass having a portion of its substance chemically altered, modified or tinted in the form of a designating mark less'in area than the surfaces of the lens but extending from the other in definite designs by subjecting limited portions thereof corresponding to the desi desired, to the rays projected from an e ectrically excited vacuum tube the duration of the exposure being only sufiicient to render the desi n perceptible'but without appreciabl a ectmg thelight transmitting or re racting powers of the lens or blank.

THEODORE B. 'DRESGHER. 

